Breaker point assembly



Dec. 1, 1942. w. s. THOMAS BREAKER POINT ASSEMBLY Filed Oct. 2, 1940gown/rm William if/zomas,

Patented Dec. 1, 1942 UNITEE STATES PATENT OFFICE.

BREAKER POINT ASSEMBLY William S. Thomas, Montoursville, Pa., assignorof ninety-five per cent to Howard S. Reese,'Williamsport, Pa, and fiveper cent to Christian K. Nielsen, Washington, D. C.

Application October 2, 1940, Serial No. 359,445

1 Claim. (Cl. 200-30) This invention relates to electrical contactmounting of the arms I2 and I 3 is Well underpoints, especiallyapplicable to ignition systems stood and a detailed description isunnecessary of internal combustion engines and it consists to the fullunderstanding of the invention. The

in the constructions, arrangements and combiarm I3 is spring-actuated asat I4, holding the nations herein described and claimed. ubbing block I5into enga e h a Cam It is well known to those skilled in the autoi7.

motive as well as other fields, that the present The arm I2 is providedwith a breaker point day construction of breaker points presents a I8,the contact face I9 of which is tapered or source of motor failure due,in most cases, to incl ned with respect to the lon itudinal axisformation of pitting between the contacts. When in e a d the arm I3embodies a breaker point pitting between the contacts occurs, one of the23 ha a C eX CO aC face 2| a d contacts will have a tit formed thereon,while to en a h po n 8 s shown n F re the other will have a pit andunless the tit and y the con ru t n of r a r p ints as shown,

pit are actually aligned during closing of the it will be obvious thatthe convex face 2| by contacts, the contacting surface is insuflicientto 3.3 reason of its convexity Will tend o p o a transmit currents forproper operation of th sliding or wiping actionon the tapered contactengine, with consequent loss of power as n face I3, thereby reducingliability of formation as liability of complete failure of the engine.of h and ts t p In 2Midition, the

It is therefore the cardinal object of the insurfaces of the breakerpoints will prevent oxivention to provide a novel construction of con-1m dation of the contact faces, as well as maintain tact points in whicha sliding or wiping action the faces free of foreign matter which wouldis inherent between points, thus eliminatin the interfere with properoperation of the distributor.

formation of a tit or pit on the contact points, While I have shown anddescribed the convex which consequently reduces the failure of a sparkea point as in m u d o the a inasystem employing the onta ts, 2.? andthe tapered contact is on the arm l2, re- More specifically, it is anobject of th inversal of the contacts is possible, without devention toprovide a pair of cooperating eonparting from the eficiency of theassembly. tacts, one of which has a convex face comple- The breaker p0ts I 8 and 0 will be cut from mental to a tapered surface of the othercontact, y n i a ba s of tungst of p oper lengt s, thereby providing awiping or cleaning effect be- :31) and as Shown, the point W1111 includea S tween the contacts durin opening d closing 22 for rigid mountingupon the arm I2, and movements f th cgntacts the point 20 will have alength to frictionally Additional objects, advantages and features offit between p a g s 23 of the arm I3, invention will be apparent fromthe following where it is Spot-welded or otherwise secured. descriptionconsidered in conjunction with the 235 The breaker assembly, namely, thearms l2 accompanying drawing, wherein and it are to be made in sizes andso constructed Figure 1 is a top plan View of a distributor as toreadily replace similar arms of standard with the cover removed, ha ingm i ti distributers, thereby permitting installation of installedtherein. the assembly upon distributers already in use.

Figure 2 is a vertical section through the disn) In Figures 5 d 6, amodified m Of y tributer casing, showing the breaker points in breakeras m y s s wn, in w ch he sw n end i ti ing arm I3 is provided with aspring for mount- Figure 3 is a perspective view of one of the ing of abreaker point o produce a greater breaker arms illustrating the contacthaving a S g or wipi g effect than is possible in the di 45 first formdescribed.

Figure 4 is a similar view of the other contact. In t m f the a m l2 anda r p i Figure 5 is a view similar to Figure 1, illusit remain as firstdescribed, but the arm I3 trating a modified form of one of the breakeris of shorter length and has fixed inwardly of arms. the free endthereof, as at 24, a flat steel leaf Figure 6 is a perspective view ofthe breaker 5O spring 25. The spring 25 will include parallel arm shownin Figure 5. flanges 25 corresponding to the flanges 23 for There isillustrated a distributor casing In of mounting of the breaker point 20.conventional form, having an assembly plate I I The relation of thepoints I8 and 28 will be for mounting of an adjustable contact arm I2the same as before described, but in operation,

and a cam actuated swinging arm I3. The the spring I4 being of greaterstrength than the leaf spring 25 a decided sliding or wiping actionbetween the contacts is obtained.

I have particularly described the invention as applied to a breakerassembly for a distributer, but obviously, the construction isapplicable to many make-and-break devices for electrical circuits.

While I have shown and described preferred forms of the invention, thisis by way of illustration only, and I consider as my own, all suchmodifications in structure as fairly fall within the scope of theappended claim.

I claim:

An ignition timer for internal combustion engines comprising a fixed armand a movable arm, said movable arm having a flat leaf spring fixedinwardly of the free end of the arm and projecting therebeyond, acontact carried adjacent the projecting end of the spring, a contactcarried by the fixed arm complemental to the first named contact, one ofsaid contacts having a tapered face cooperative with an arcuate face ofthe other contact, whereby a sliding action is effected between thecontacts at and during the period of contacting engagement and means forintermittently moving the movable arm.

WILLIAM S. THOMAS.

